Dear Bill,
Your question is interesting and I too would like to know the answer. It
seems to me that there need not necessarily be a connection between the
origin of competence for xylem cell (i.e., tracheary element)
differentiation and the origin of competence for apical meristem-derived
cells to differentiate into procambial fusiform cells. In extant plants,
procambium originates first, before TE differentiation; hence, if we
believe that ontogeny recapitulates phylogeny, procambial development would
have preceded xylogenesis. The June 25, 1992, issue of Nature (vol 357, pp
641, 683) has some relevant articles.
RAS
In message 13 Mar 1996 06:05:09 -0800, WSCOHEN at ukcc.uky.edu (bill) writes:
> Can anyone shed light on the origin of xylem in early Devonian vascular
> plants? For example, did ground meristem give rise to procambium? Any
> insights would b e appreciated!
>> William S. Cohen Voice Mail: [606] 257 1030
> School of Biological Sciences FAX: [606] 257 1717
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Rod Savidge, PhD, Professor | E-mail: savidge at unb.ca
Faculty of Forestry and \|/
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